We're dividing 34739737 by 399 
The aim is to understand the frequency of 399 in 34739737.

On to step 1:
If we divide 3 by 399, we get 0 and a remainder of 3.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Append the next digit (4) from the dividend to 3 and continue with: 34 / 399

Moving on to step 2:
399 goes into 34 0 times with a remainder of 34.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Deduct 0 from 34 and we're left with 34.
Bring next digit (7) of the dividend behind the 34 and repeat the process: 347 / 399

Going ahead to step 3:
347 divided by 399 is 0 with a remainder of 347.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 347, we end up with 347.
Take the next digit (3) from the dividend and append it to 347, then repeat: 3473 / 399

Going ahead to step 4:
When dividing 3473 by 399, we get 8 with a remainder of 281.
The number 8 becomes the next digit in our result. 
Result so far: 8.0
Subtracting 3192 from 3473 leaves us with 281.
Grab the next digit (9) from the dividend, add it to 281, then carry on: 2819 / 399

Let's proceed to step 5:
399 can be fit into 2819 7 times, resulting in a remainder of 26.
Put 7 as the next digit of the answer. 
Result so far: 87.0
The remainder is 26 after subtracting 2793 from 2819.
Grab the next digit (7) from the dividend, add it to 26, then carry on: 267 / 399

Step 6:
267 divided by 399 is 0 with a remainder of 267.
Use 0 as the next digit of our solution. 
Result so far: 870.0
Subtract 0 from 267 to get 267.
Include the next digit (3) from the dividend after 267, then repeat: 2673 / 399

Going ahead to step 7:
399 goes into 2673 6 times with a remainder of 279.
Use 6 as the next digit of our solution. 
Result so far: 8706.0
Deduct 2394 from 2673 and we're left with 279.
Bring next digit (7) of the dividend behind the 279 and repeat the process: 2797 / 399

Going ahead to step 8:
399 goes into 2797 7 times with a remainder of 4.
Put 7 as the next digit of the answer. 
Result so far: 87067.0
Subtract 2793 from 2797 to get 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

Going ahead to step 9:
40 divided by 399 is 0 with a remainder of 40.
Use 0 as the next digit of our solution. 
Result so far: 87067.0
Deduct 0 from 40 and we're left with 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Going ahead to step 10:
The number 399 fits into 400 1 times, leaving a remainder of 1.
The number 1 becomes the next digit in our result. 
Result so far: 87067.01
The remainder is 1 after subtracting 399 from 400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Let's proceed to step 11:
10 divided by 399 is 0 with a remainder of 10.
Put 0 as the next digit of the answer. 
Result so far: 87067.01
If we take 0 away from 10, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

On to step 12:
The number 399 fits into 100 0 times, leaving a remainder of 100.
The next digit of our result is 0. 
Result so far: 87067.01
If we subtract 0 from 100, we get 100.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1000, and continue the process.

After the division, we end up with 87067.01 and a remainder of 0.001.